This invention concerns a blood diluent especially suitable for use in electronic enumeration and sizing of blood cells, determination of hemoglobin and their collective indices and platelet parameters in a single blood cell sample by means of suitable electronic instrumentation. The diluent comprises a stable water solution of chemical salts providing an electrolytic solution to which a blood sample can be added so as to dilute the larger number of red blood cells, white blood cells, platelets and other blood components and enable the desired parameter of these blood components to be measured, counted and evaluated.
The invention also concerns the use of a modified embodiment of the diluent in veterinary laboratory testing applications.
It is a common medical diagnostic procedure to analyze and test a blood sample of a patient in order to make certain classic determinations with respect to the blood sample. This procedure is an important tool for the physician. Six characteristically important parameters are referred to as red blood cell count (RBC), the hematocrit (HCT), the hemoglobin (HGB), the mean corpuscular volume (HCV), the mean corpuscular hemoglobin (MCH), and the mean corpuscular hemoglobin concentration (MCHC). A seventh important determination is white blood cell count (WBC). An instrument which will accept a patient's blood sample and process the blood sample automatically and continuously to provide the parameters or determinations enumerated is described and claimed in U.S. Pat. No. 3,549,994. Said Pat. No. 3,549,994 provides acceptable definitions of said parameters and illuminates the problems to be solved in the handling of the blood sample as it is drawn through the fluid system of said patented apparatus.
Coulter Electronics, Inc. of Hialeah, Florida also manufactures and sells other blood cell counting and analyzing instruments which are less sophisticated than the apparatus of said U.S. Pat. No. 3,549,994, but which are operated to determine red blood cell and white blood cell count, hemoglobin concentration and their collective indices such as HCT, MCV, MCH and MCHC. The multi-purpose diluent embodying the invention is suitable for use with such instrumentation as well, where problems attendant the successful handling of the blood sample are the same. In other words, this blood diluent is compatible with other electronic particle analysis instruments utilizing the so-called Coulter principle. Such instruments may be referred to herein, at times, selectively by the registered trademark "COULTER COUNTER.RTM." owned by Coulter Electronics, Inc.
In U.S. Pat. No. 3,962,125 issued for the invention "Multi-Purpose Diluent For Use In Blood Analysis By Electronic Instrumentation Of The Coulter Type", there is described and claimed a diluent especially suitable for eliminating the problems attendant the use of prior blood diluents which use sodium azide as the effective bacteriostatic agent. U.S. Pat. No. 3,962,125 illuminates further the characteristics of red blood cells which must be taken into account in order to provide a practical and suitable diluent.
The diluent of U.S. Pat. No. 3,962,125 did not focus on suitability thereof for use in making platelet parameter determinations. At the time of the invention of said U.S. Pat. No. 3,962,125, Coulter Electronics, Inc. had marketed an instrument known as the Model "S" and Model "S"-Sr. which did not have the capability for making platelet determinations. Consequently, the diluent of U.S. Pat. No. 3,962,125 was not concerned with the critical factor of bubble formation by reason of detergent action thereof which would cause bubbles capable of interfering with the enumeration of platelets by electronic instrumentation capable of making such determinations. Since that time, Coulter Electronics, Inc. has introduced electronic instrumentation known as the Model "S"-Plus which does have platelet determination capability and in connection with the multi-purpose diluent embodying the invention is especially suitable for dilution of blood samples which are drawn through such instruments during its operation.